Percent difference in median methylation (smokers - nonsmokers) Chromosome Gene CpG NEST MoBa (b) p-value (a) 5 AHRR cg05575921 0.
0019): two in CYP1A1 and one in AHRR, genes known to be involved in the detoxification of compounds from tobacco smoke via the aryl hydrocarbon receptor (AhR) signaling pathway; and two CpGs in GFI1, a gene that has not previously been implicated in responses to tobacco smoke.
The authors also studied the functional implications of this methylation change and found that methylation at AHRR cg05575921 was associated with AHRR expression.
In our study, maternal smoking, assessed objectively by cotinine, displayed a dose-dependent association with lower methylation of AHRR CpGs and higher methylation of CYP1A1 CpGs in cord blood.
In that paper, smoking-induced alteration of AHRR CpGs (including our top CpG) was seen in both B lymphoblastoid cells and in an independently collected sample of alveolar macrophage cells collected from bronchial lavage.
For our top CpG AHRR cg05575921, the percent difference in median methylation was 0.
But again, our top finding for AHRR cg05575921 due to maternal smoking was also reported in adult smokers in two different cell types--alveolar lung macrophage DNA and lymphoblast DNA (Monick et al.